Obviously this is a typo and although there were no effects observed
it's probably better to fix it.
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
        timing.hor_sync_end = timing.hor_sync_start + var->hsync_len;
        timing.hor_total = timing.hor_sync_end + var->left_margin + dx;
        timing.hor_blank_start = timing.hor_addr + dx;
-       timing.hor_blank_end = timing.hor_total - dy;
+       timing.hor_blank_end = timing.hor_total - dx;
        timing.ver_addr = cyres;
        timing.ver_sync_start = timing.ver_addr + var->lower_margin + dy;
        timing.ver_sync_end = timing.ver_sync_start + var->vsync_len;